Copyright Statement

Copyright 2007 Arbora Publishers

Abstract

Genetic parameters were estimated for diameter at breast height (DBH), height and core basic density
(CBD) from ten second-generation control-pollinated Eucalyptus globulus progeny trials in Australia.
Using multi-site analysis we aimed, firstly, to determine a suitable linear model to fit to the data and,
secondly, to determine the relative importance of additive and non-additive genetic effects. A model with
heterogeneous additive and error variances was used for all traits. The individual site heritabilities
averaged 0.12 for DBH, 0.11 for height and 0.44 for CBD. Over all sites, the ratios of SCA (specific
combining ability) and subrace to additive genetic variance for DBH (0.25 and 0.5) and height (0.30 and
0.25) were significantly greater than zero, but not for CBD (0.08 and 1.00). Inter-site additive genetic
correlations were 0.71 for DBH, 0.72 for height and 1.07 for CBD, and all were not significantly different
from 1. This study suggests that, for early growth, levels of dominance are comparable to additive genetic
effects in this breeding population and there are significant genetic differences between subraces. In
contrast, for CBD most genetic variation was additive and significant differences between subraces could
not be detected with the small sample.